JPS5815850A - Apparatus for measuring gas in blood - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring gas content in the blood of a patient.

Several methods are known in the art for measuring the partial pressure of gases contained in a patient's blood. Conventional methods involve taking a blood sample from a patient with a catheter and sending the sample to an analysis site to analyze the gases in the blood. Although the blood test itself can be performed in two to three minutes using modern highly automated equipment and provides a complete blood gas analysis, the entire process from blood sampling to obtaining analytical results is very time consuming.

Moreover, such automated analysis equipment is sophisticated and expensive.

One method of analyzing blood samples is the so-called bubble method, in which a blood sample from a patient is brought into contact with gas bubbles such that the gas bubbles provide a sample representative of the gas content of the blood. do. The gas content is determined from the sample, for example by infrared spectroscopy.

This method is somewhat inaccurate, complicated and time consuming.

The content of gases in the blood, especially CO2, is a very useful indicator for blood circulation and respiration efficiency and metabolism, such as in surgical procedures. Since this index sensitively responds to various changes, there has been a need for a simple method and device that can more quickly measure the gas content in blood.

One device for measuring 002 content in blood is shown in US Pat. No. 3,987,303. This measurement is
The skin is used directly by diffusing blood gases within the capillary tissue of the skin through a gas-permeable membrane into a chamber containing a suitable gaseous medium. C in blood
02 reaches the same content on both sides of the membrane, thereby COa
The content can be determined from the sample in the chamber. Even with this method, the measurements are not continuous, but are based on individual sampling by constantly scraping off part of the top layer of the skin. Based on such direct skin sampling (measurements are susceptible to various factors that induce inaccuracy, such as skin uncleanness), it is also difficult to set the device tightly on a defined area on the skin. is difficult.

One practical method used in operating rooms and hospital rooms is
An oxygen supply device (oxygena) connected to the patient's circulatory system
The CoQ content of blood is measured from the exhaust gas of a tor. A gas permeable membrane is used in the oxygenator that separates a chamber through which the patient's circulating blood passes and a chamber through which Gos gas or O1/Dos mixture gas passes;
02 content can be measured continuously. However, since the purpose of the oxygenator is to add oxygen to the patient's blood and remove excess CO2 from the blood, it is necessary to supply a considerable amount of the above gas into the circulating blood. Therefore, the oxygenator chambers must be substantially equal in size. Since the 02 and Gos content of the patient's blood must be kept within a somewhat strict range, the gas diffusion that takes place through the gas-permeable membrane must be precise and under control; The area of the membrane is usually about 1 m2. Given the above and given that the gas content of the bloodstream through the oxygenator has a partial gradient, measuring the gas content of the blood from the exhaust gas of the oxygenator is highly inaccurate. It should be accompanied by

It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and to provide a simple and effective device for measuring gases contained in a patient's blood using gas diffusion through a permeable membrane. It is in. Another object of the present invention is to provide an apparatus that can continuously measure gases in blood and is inexpensive to manufacture and operate.
It is about providing. Another object of the present invention is to provide an apparatus that is particularly suitable for measuring the content of CO2 and O2 and can quickly change the content. Yet another object of the present invention is to provide a device suitable for use as part of a system connected to a patient's blood circulation in conjunction with an oxygenator, hemodialysis machine, or the like.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

The unit 1 shown in FIG. 1 has a chamber 2 into which a carrier gas, such as air, is supplied and a chamber 3 through which the patient's circulating blood is passed.

The unit includes a gas inlet vibe 7, a gas outlet vibe 8,
A blood inlet vibe 5 and a blood outlet vibe 6 are connected so that blood and gas flow in the direction indicated by the arrow. The unit 1 is provided with a gas permeable membrane, for example silicone rubber, which separates the nayambas 2 and 3.

The apparatus shown in FIG. 1 is equipped with a gas analysis unit 9 for analyzing the content of COs, O2, and other gases that may be contained in the surface liquid.

In the present invention, gases in the patient's blood can diffuse from chamber 3 through membrane 4 into the carrier gas in chamber 2.1. COs and o2 will be in the same amount on both sides of the membrane 4. The sample gas in the chamber 2 obtained in this way represents the 00m and 02 content in the blood and also changes according to the change in its content, so that this 9 content can be measured by an infrared gas analyzer and an oxygen sensor. general purpose means.

Measured by method.

In the embodiment shown in FIG. 1, the sample gas is provided within a carrier gas and transported by the carrier gas to the analysis unit. The sample gas is transported to the analysis unit 9.
This can be done continuously or intermittently in pulses by using a sample aspiration pump (not shown) that is part of the. For example, this supply is 1 at a speed of 50 m11 min
By supplying for 0 seconds, one production can occur every 1 to 5 minutes. When the sample gas is continuously conveyed, a flow rate of 200 m1/min or less is preferable. After the sample gas is passed through the analysis unit, it is returned to chamber 2 of unit 1 and serves as a carrier gas. That is, the flow of carrier gas forms a closed loop. The advantage of this device is that the carrier gas is repeatedly circulated.
This means that the carrier gas is very representative of the fresh sample gas that is created, eliminating the drawbacks of sample gas compared to devices where fresh carrier gas is continuously drawn and supplied to chamber 2. do. Therefore, the first
In the embodiment shown, the mixing of the carrier gas with the fresh sample gas produced in chamber 2 is not critical to the gas content, so unit 1 has a simpler design. Can be done. On the other hand, an open-loop system is one between unit 1 and analysis unit 9.
The above drawback is that the carrier gas has to travel a long distance within the unit 1.
You can compensate more.

FIG. 2 shows an embodiment of a unit 1 in which the flow of carrier gas can be advantageously used in both closed-loop and open-loop systems. As shown in FIG. 2, the unit has a member 10 forming a chamber 2 and a member 11 forming a chamber 3, the member 10 having a plurality of grooves (or ducts) 12, and the member 11 having a plurality of grooves (or ducts) 12. A groove (or duct) 13 is provided. Part 10.11
are closely joined by member 27. The intermediate lip j4.15 in the groove constitutes a support surface for the membrane 4.

The time to obtain sample gas for determining the content of CO2 and C2 in blood is influenced by the design, length, volume and diffusion surface of the carrier gas channel 12. A more complex and/or longer groove 12 is required if the new carrier gas supplied into the chamber 2 is likely to have an undue influence on the produced sample gas to be analyzed.

On the other hand, the smaller the volume of the groove 12 and the overall carrier gas and sample gas flow system, the larger the diffusion surface, the shorter the time to create the sample gas and the less responsive the system is to changes occurring in the gas content of the blood. It gets faster. In addition to the above, in the present invention a sample gas analysis chamber can be arranged in close proximity to the chamber 2, e.g. The chamber can be configured to form an analytical system for When using infrared gas analysis means as the analysis means, it is sufficient to provide the analysis chamber with a suitable window surface. If desired, it is easy to provide an oxygen sensor in the analysis chamber.

It is also possible to pass the sample gas to a separate analyzer for CO2 measurements and to perform C2 measurements in chamber 2 or in a separate chamber. In the embodiment shown in FIG. 3, the chamber 2 is divided into two parts 2α, 2b.
It is divided into. Portion 2b is filled with carrier gas,
It is separated from the gas circulation system consisting of part 2α, pipe 7.8 and analysis unit 9 to form an independent analysis chamber, into which the gases in the blood enter by diffusion from chamber 3, in particular 02 can be measured by one or several sensors 27. In this example, C0
2 content can be measured by a carrier gas circulation system, and the portion 2cL of the chamber 2 can have a groove structure as shown in FIG.

02 content measurement is very advantageous due to the slow operation of the 0w sensor. Since the analysis chamber 2b also contains a carrier gas, the accuracy of the measured gas content value depends on the properties of the membrane 4 and, for example, on the blood flow rate. The analysis chamber 2b can also be used to measure other gases in the blood.

In all the above cases, the unit 1 is an economical disposable product of very simple design and can be coupled to the system separately for each patient, thus improving the applicability of the overall system. The capacity of the gas chamber 2 is preferably 5 cd or less to make measurements simple and effective.

Chamber 3 has a considerably larger capacity than chamber 2, in fact up to about 10 times the capacity.

This is in order to sample the gas sufficiently quickly (and thus shorten the sampling interval). This is also done by the area of the membrane 4. This area is preferably 250 (M11
'Less than.

FIG. 4 shows how the device of the invention is connected to a blood processing device 17, such as an oxygenator or a hemodialysis device, which is connected to the blood circulation system of a patient 16. . The device 17 is provided with two chambers 21.22, which in practice constitute a complex duct or channel system. The chambers are separated by a membrane 23, which is permeable to gases in the case of oxygenators and permeable to certain liquids and substances in hemodialysis machines. The chamber 21 is connected to the circulatory system of the patient 16 by a supply duct 18, and the chamber 22
is connected to the media flow system 2o. Also connected to the device 17 is a so-called bubble trap and flow-generating pump for the blood supplied to the patient (not shown in FIG. 4). Once the blood sample has been subjected to the necessary processing in the device 17, it is passed through the duct 24 to the unit IK according to the present invention, and then returned to the patient through the duct 19. As a practical precaution, the system is also provided with a bubble trap (not shown) downstream of unit 1. By analyzing the blood supplied to a patient according to the invention, it can be ensured that the blood contains appropriate COz and o2. The information obtained by the analysis unit 9 can be used to control the permeation of substances through the membrane 23 and, if necessary, to control the blood supply to the patient by means of valves 26 and by-passes. The system is schematically illustrated by arrows 24°25
). In addition, by connecting units 1 and 17 in reverse, it is also possible to obtain information on gas content before blood processing and test the patient's metabolism, heart condition, blood circulatory system, respiratory system, etc. .

The present invention can also be used with respect to fluid systems related to the organs of the human body, such as the kidneys, to perform measurements on other fluids instead of blood.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of the device of the present invention; Fig. 2 is an exploded explanatory diagram showing one embodiment of a unit forming a part of the device; Fig. 3 is a diagram showing the principle of another embodiment. FIG. 4 is a diagram illustrating an example of the use of the device of the invention connected to a blood processing system connected to a patient's blood circulatory system. Patent applicant: Instrumentarium Osakei Tiny (2 others) Engraving of the drawings (no changes to the contents) 11 NiMji: 2 WJKi: 3 0 11 Yama 14 Procedural amendment February 1930-1939 3rd Showa ke Z year patent application No. 2 / ρgume ζ 1 No. 2, the name of the invention and the relationship between Patent Applicant Address fi+”;4.

Claims (1)

[Claims] (In an apparatus for measuring gases in the blood of 1 to 6 people, especially CO2 and 02; a first chamber (2) to which a carrier gas is supplied; considerably larger than the chamber; A unit comprising a second chamber (3) connected to the patient's artery or vein and continuously supplied with blood flow, and a gas permeable membrane (4) separating the first and second chambers. (
1); and means (9) for measuring a sample gas representative of the gas content in the blood formed by the gas contained in the blood diffusing into the carrier gas through the membrane. Device. 2. The device of claim 1, wherein said chambers (2, 3) and membrane (4) are dimensioned to maximize diffusion of said gas. (3) a chamber in which a carrier gas is continuously passed through the first chamber (2) and said sample gas produced in said chamber (2) is caused to be continuously passed through the measuring means (9); 4. A device according to claim 3, forming a closed loop through the measuring means. (5) The sample gas is passed through the measuring means (9) in a pulsed manner when the content of the gas to be measured reaches a sufficient equilibrium state through the membrane (4). The device according to item 4 or item 4. (6) The sample gas is continuously supplied at such a rate that the content of the gas to be measured reaches an equilibrium state through the membrane (4) to the molecules. The device according to item 4. (7) The device according to claim 6, wherein the speed is 200 m17 minutes or less. (8) The above-mentioned unit) (1) as described in any one of claims 1 to 7, wherein (1) is a member that is replaceable with other parts of the device, preferably disposable. Device. (9) In order to measure the content of the required gas from the sample gas, the rod 1 chamber (2) is divided into at least two parts (2α, 2b), one of which (2b)
4. The apparatus according to claim 1, wherein the analysis chamber is separate from the carrier gas circulation system and is an independent analysis chamber. (1G) The unit (1) comprises a first member (10) defining a first chamber (2) separated by a membrane (4).
) and a second member (11) defining a second chamber (3).
) The device according to any one of claims 1 to 9, comprising: Ql) The first and second members have structures (12, 13) that make the first and second chambers into ducts, respectively, and the carrier gas and sample gas in the duct structure (12) of the first member are The moving length is considerably longer than the moving length of the blood in the duct structure (13) of the second member, and the duct structure (12) for the gas has a considerably smaller capacity than the duct structure for blood. 11. The apparatus according to claim 10, wherein the amount of carrier gas is optimized to produce a sufficient amount of sample gas. az such that the direction of the ducts in the duct structure of the first member is approximately perpendicular to the direction of the ducts in the duct structure of the second member, and the intermediate lip (14, 15) between the ducts supports the membrane (4). 12. The apparatus according to claim 11. Country 0 The device according to any one of claims 1 to 12, wherein the area of the membrane is 25ocrIL2 or less. α4 The device according to any one of claims 1 to 13, wherein the first chamber (2) has a capacity of 5 d or less. a9 The device according to any one of claims 1 to 14, wherein the carrier gas is air.